Hello my name is XXXXX XXXXX I and will be more than happy to assist you.
Cadillac does have problem with coolant leaks in the water pump area.
The good new is it should not be a head gasket. Most likely it is the Water Pump Cover. GM does have a bulletin out about this. Click on link Below.
I also included the repair procedure so you can see if this is something you may want to do your self.
GM Coolant Leak Service Bulletin
Water Pump Cover Replacement